Power Loss on Hot/Humid Day
06-19-2005, 10:40 AM
#1
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Power Loss on Hot/Humid Day
Hi all, I'm new to this forum (will somebody please redirect me to the appropriate board if I've posted in the wrong place?)
I just searched through this site for info on a problem I had early last week and didn't come up with this scenario...I'm hoping somebody out there can provide me some insight.
I was driving home from work early last week in my 2002 WRX (stock)...the weather here in NY was about 93F and very humid. About 15 min into my commute I lost acceleration and the car bogged down anywhere above 3000 RPM. I limped for another 5 miles as the problem worsened..I pulled over when I couldn't put a load on the engine above 2500RPM.
While stopped I lifted the hood and felt that the engine was very hot (although as mentioned we were in a heat wave so I couldn't really tell how hot "hot" was...). The temperature gauge in the car did not indicate that I was over heating or that the temperatures were above normal...
Anyway, I let the car cool for about 30 min at which time I started it up and managed to drive it to the dealership near by...the problem was much better but had not disappeared...
The dealer had the car for 3 days and reported that they did observe the problem but could not come up with any smoking guns (turbo was pronounced healthy and they did not find any leaks or restrictions).....they had a rep from the factory look at the car on day 3 and finally decided that a) I might have gotten a batch of bad gas or b) that the weather had effected the car's performance...
When I picked the car up the problem was still noticable as hestitation and "momentary bogging down" (for lack of a better term)...but it was almost empty on fuel..I filled the tank and the problem has definately improved...note however, that at the same time the temperature in NY is back to 73F...
One more note...I never got a CEL turn on..
So I guess I have a couple of questions (and a rather windy post)...
1. I'm always a little skeptical of the "bad gas" explanation...it sounds like a catch all phrase to me - although since I refilled the tank I have seen the problem improve...anyone think this could be it?
2. The dealer said that this problem has been reported before as something that happens in hot an humid weather...I'm having trouble with that too however, because I've got 70K on the car and never experienced it before...has anybody else ever had this problem (i'm thinking folks in Florida and the deep south must have come across this if it really was a problem)....
Thanks in advance...am interested in hereing what folks here think it might be/could have been...
Joeman
I just searched through this site for info on a problem I had early last week and didn't come up with this scenario...I'm hoping somebody out there can provide me some insight.
I was driving home from work early last week in my 2002 WRX (stock)...the weather here in NY was about 93F and very humid. About 15 min into my commute I lost acceleration and the car bogged down anywhere above 3000 RPM. I limped for another 5 miles as the problem worsened..I pulled over when I couldn't put a load on the engine above 2500RPM.
While stopped I lifted the hood and felt that the engine was very hot (although as mentioned we were in a heat wave so I couldn't really tell how hot "hot" was...). The temperature gauge in the car did not indicate that I was over heating or that the temperatures were above normal...
Anyway, I let the car cool for about 30 min at which time I started it up and managed to drive it to the dealership near by...the problem was much better but had not disappeared...
The dealer had the car for 3 days and reported that they did observe the problem but could not come up with any smoking guns (turbo was pronounced healthy and they did not find any leaks or restrictions).....they had a rep from the factory look at the car on day 3 and finally decided that a) I might have gotten a batch of bad gas or b) that the weather had effected the car's performance...
When I picked the car up the problem was still noticable as hestitation and "momentary bogging down" (for lack of a better term)...but it was almost empty on fuel..I filled the tank and the problem has definately improved...note however, that at the same time the temperature in NY is back to 73F...
One more note...I never got a CEL turn on..
So I guess I have a couple of questions (and a rather windy post)...
1. I'm always a little skeptical of the "bad gas" explanation...it sounds like a catch all phrase to me - although since I refilled the tank I have seen the problem improve...anyone think this could be it?
2. The dealer said that this problem has been reported before as something that happens in hot an humid weather...I'm having trouble with that too however, because I've got 70K on the car and never experienced it before...has anybody else ever had this problem (i'm thinking folks in Florida and the deep south must have come across this if it really was a problem)....
Thanks in advance...am interested in hereing what folks here think it might be/could have been...
Joeman
06-19-2005, 03:25 PM
#4
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Car Info: 02 Impreza WRX sedan
Origami posted by Joeman
I don't quite understand..this wasn't reduced performance, this was no performance...the car practically stalled...is this common?
I don't quite understand..this wasn't reduced performance, this was no performance...the car practically stalled...is this common?
EDIT: If you fill out your Location field (general location is good enough - NY) in your Profile, it's easier for us to remember why you experience such weather.
--
0==WW==0
"…axles of evil…" - george w. bush
06-19-2005, 07:52 PM
#5
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WW - thanks for the input....
Yeah, I think this is kinda strange too, 105+ suggests that some folks out there have really pushed these things to some extremes (from ambient perspective)...as mentioned in the original post I'm sure some people in the Alabamas, Floridas, South Carolinas have driven in conditions like I mention which is why I'm not really ready to believe the dealer's explanation...anybody got some guesses what might have gone wrong? I guess I'm just trying to prepare for the worst....(and decide if I should join AAA)....
Yeah, I think this is kinda strange too, 105+ suggests that some folks out there have really pushed these things to some extremes (from ambient perspective)...as mentioned in the original post I'm sure some people in the Alabamas, Floridas, South Carolinas have driven in conditions like I mention which is why I'm not really ready to believe the dealer's explanation...anybody got some guesses what might have gone wrong? I guess I'm just trying to prepare for the worst....(and decide if I should join AAA)....
06-20-2005, 12:20 AM
#6
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im no mechanic but i think your problem is beyond bad gas or temperature. have you checked your fuel system, fuel pump injectors etc? Also maybe wastegate issues/boost leak? wish i could be of more help
06-20-2005, 10:15 AM
#7
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Joeman, I live in the Bronx and drive to the city every day and Long Island on Wednesday's. I noticed a little of what you described as bogging but my car has not reacted the way your car has. I agree with overacheiver, that you may have other problems..../
06-20-2005, 10:25 AM
#8
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Car Info: 03 WRX Sedan MBP/17X7.5 SSR Comps/225 Kumho MX
Something else is going on. I drive my 03 WRX in lots of 90's and 100+ degree weather. High air temps definitely reduce the effectiveness of turbos, but it doesn't cripple the car, it just doesn't accelerate quite as fast as in cooler weather. I've never noticed ill effects caused by high humidity. Was your gas tank real near empty when this first happened?
If the fuel tank was very close to empty, your fuel pump may have been sucking water that had collected at the bottom of the tank. Higher RPMs may have put more demand on the pump causing it to suck lower into the tank, hence: more water.
Vapor lock? Not sure how the fuel system works in the subie but this problem is more likely in hot weather with a nearly empty tank.
Defective gas cap?
A can of fuel dryer dumped into the tank the next time you fill up wouldn't hurt.
If the fuel tank was very close to empty, your fuel pump may have been sucking water that had collected at the bottom of the tank. Higher RPMs may have put more demand on the pump causing it to suck lower into the tank, hence: more water.
Vapor lock? Not sure how the fuel system works in the subie but this problem is more likely in hot weather with a nearly empty tank.
Defective gas cap?
A can of fuel dryer dumped into the tank the next time you fill up wouldn't hurt.
Last edited by yzercyber; 06-20-2005 at 10:41 AM.
06-20-2005, 11:22 AM
#9
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Join Date: Mar 2003
Location: Phoenix, AZ
Posts: 2,023
Car Info: Subaru Impreza WRX 2002
Originally Posted by Joeman
WW - thanks for the input....
Yeah, I think this is kinda strange too, 105+ suggests that some folks out there have really pushed these things to some extremes (from ambient perspective)...as mentioned in the original post I'm sure some people in the Alabamas, Floridas, South Carolinas have driven in conditions like I mention which is why I'm not really ready to believe the dealer's explanation...anybody got some guesses what might have gone wrong? I guess I'm just trying to prepare for the worst....(and decide if I should join AAA)....
Yeah, I think this is kinda strange too, 105+ suggests that some folks out there have really pushed these things to some extremes (from ambient perspective)...as mentioned in the original post I'm sure some people in the Alabamas, Floridas, South Carolinas have driven in conditions like I mention which is why I'm not really ready to believe the dealer's explanation...anybody got some guesses what might have gone wrong? I guess I'm just trying to prepare for the worst....(and decide if I should join AAA)....
You might see increased turbo lag in a hot climate, as the intercooler won't work as efficiently; however, humidity won't affect the intercooler because it does not rely on evaporative cooling -- just heat exchange with the passing air.
The only major problem with ambient heat and the EJ20 is having to turn on your air conditioning -- with my 02 WRX, turning on the A/C literally cripples the car. It limits boost to 13.2 PSI (I normally run 14.2), removes all low-end torque and makes downshifting extremely unpredictable (as the engine is still affected by the A/C "load" when the driveshaft should be "unloaded" in neutral). But this crippling effect by the A/C is steady, not incidental. I think the "bad gas" diagnosis was absolutely correct, and you've got nothing to worry about.
06-20-2005, 12:01 PM
#10
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Sounds like what happened to me when I got a batch of bad gas. Sure the pump said 91 but, I don't think it was even close. The Boost was soley running off of the waste gate with cut out at 7 psi. Do you have a boost gauge hooked up? If not, you should hook one up temporarly to see what you are running. Stock should be right about 14.5 psi. I've noticed slightly reduced performance when the temp hits around 95-105 around the bay area but, it is hardly noticable. As was said, altitude affects performace a whole lot more. Going to Tahoe in the summer I do notice a drop in performace.
Bill
Bill
06-20-2005, 01:32 PM
#11
Originally Posted by meilers
It is not the weather. Here in Phoenix our ambient temp ranges from 65 in the winter to 110 in the summer (F); I have very accurate (digital) gauges and there is almost no difference in my radiator or oil temp between a 65-degree-day and a 110-degree day. The engine puts out much more heat than the air around it, and thus the laws of thermodynamics dictate that the heat energy sheds from the engine to the air as long as the air is cooler than the engine. The EJ20 isn't "warmed up" until 165(f) and likes to stay at 185(f); thus ambient temp outside the car wouldn't affect it, except to allow it to warm up faster on hot days. Likewise, oil temp, EGTs, intake temp and more all seem fairly steady regardless of weather conditions (though intake temp goes down a few degrees in the winter).
You might see increased turbo lag in a hot climate, as the intercooler won't work as efficiently; however, humidity won't affect the intercooler because it does not rely on evaporative cooling -- just heat exchange with the passing air.
The only major problem with ambient heat and the EJ20 is having to turn on your air conditioning -- with my 02 WRX, turning on the A/C literally cripples the car. It limits boost to 13.2 PSI (I normally run 14.2), removes all low-end torque and makes downshifting extremely unpredictable (as the engine is still affected by the A/C "load" when the driveshaft should be "unloaded" in neutral). But this crippling effect by the A/C is steady, not incidental. I think the "bad gas" diagnosis was absolutely correct, and you've got nothing to worry about.
You might see increased turbo lag in a hot climate, as the intercooler won't work as efficiently; however, humidity won't affect the intercooler because it does not rely on evaporative cooling -- just heat exchange with the passing air.
The only major problem with ambient heat and the EJ20 is having to turn on your air conditioning -- with my 02 WRX, turning on the A/C literally cripples the car. It limits boost to 13.2 PSI (I normally run 14.2), removes all low-end torque and makes downshifting extremely unpredictable (as the engine is still affected by the A/C "load" when the driveshaft should be "unloaded" in neutral). But this crippling effect by the A/C is steady, not incidental. I think the "bad gas" diagnosis was absolutely correct, and you've got nothing to worry about.
06-20-2005, 01:39 PM
#12
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Theoretically this could happen. If your ECU is used to the typically New York state weather being cool and all the sudden it experiences vastly different inlet air temps it could def. retard the timing enough to cause "no performance" like conditions. The thing you need to remember is that if that is the case your ECU did you a favor and kept you from detonating. Remember that the hotter air gets the less oxygen content it has which puts more demand on octane (i.e. air/fuel). Hope this helps a little. Keep us updated.
06-20-2005, 02:01 PM
#13
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I just had my '02 WRX in the Subaru shop this afternoon with the exact same problem, mine was more pronounced during and after a moderate righthand corner or a moderate to heavy deceleration.
However, about 3 hours after the check it was just as crippled as Joeman described.
The techs at the dealer said there have been a few cases of this and that the "tech line" said that they replaced the entire pickup assembly, and that the "sock" might have gotten contaminated.
Since I first noticed this problem about 5 days ago I have noted:
No immediate change in RPM when depressing the clutch (no change in throttle input) during the episode
NOT bad gas, 5 different gas stations
Not water in the gas, problem got more pronounced after adding 'heat'
Ambient temperature doesn't seem to matter, however letting the car sit for 30+ min helps
No boost fluctuation.
Every gear
At first just right hand corners, both roads 35mph limit, with moderate throttle
Later hesitation, sometimes stall, after moderate/heavy decel
Does anyone know where the post about changing your fuel pump is?
Does anyone know if I could run a Walboro? 255 fuel pump w/o larger turbo, injectors, or
computer mod?
Anyone have any other ideas?
Thanks
However, about 3 hours after the check it was just as crippled as Joeman described.
The techs at the dealer said there have been a few cases of this and that the "tech line" said that they replaced the entire pickup assembly, and that the "sock" might have gotten contaminated.
Since I first noticed this problem about 5 days ago I have noted:
No immediate change in RPM when depressing the clutch (no change in throttle input) during the episode
NOT bad gas, 5 different gas stations
Not water in the gas, problem got more pronounced after adding 'heat'
Ambient temperature doesn't seem to matter, however letting the car sit for 30+ min helps
No boost fluctuation.
Every gear
At first just right hand corners, both roads 35mph limit, with moderate throttle
Later hesitation, sometimes stall, after moderate/heavy decel
Does anyone know where the post about changing your fuel pump is?
Does anyone know if I could run a Walboro? 255 fuel pump w/o larger turbo, injectors, or
computer mod?
Anyone have any other ideas?
Thanks
06-20-2005, 02:12 PM
#14
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Join Date: Jan 2005
Location: I gotta have more cow bell!!!!
Posts: 9,198
Car Info: 05 STi
Originally Posted by knight1833
I just had my '02 WRX in the Subaru shop this afternoon with the exact same problem, mine was more pronounced during and after a moderate righthand corner or a moderate to heavy deceleration.
However, about 3 hours after the check it was just as crippled as Joeman described.
The techs at the dealer said there have been a few cases of this and that the "tech line" said that they replaced the entire pickup assembly, and that the "sock" might have gotten contaminated.
Since I first noticed this problem about 5 days ago I have noted:
No immediate change in RPM when depressing the clutch (no change in throttle input) during the episode
NOT bad gas, 5 different gas stations
Not water in the gas, problem got more pronounced after adding 'heat'
Ambient temperature doesn't seem to matter, however letting the car sit for 30+ min helps
No boost fluctuation.
Every gear
At first just right hand corners, both roads 35mph limit, with moderate throttle
Later hesitation, sometimes stall, after moderate/heavy decel
Does anyone know where the post about changing your fuel pump is?
Does anyone know if I could run a Walboro? 255 fuel pump w/o larger turbo, injectors, or
computer mod?
Anyone have any other ideas?
Thanks
However, about 3 hours after the check it was just as crippled as Joeman described.
The techs at the dealer said there have been a few cases of this and that the "tech line" said that they replaced the entire pickup assembly, and that the "sock" might have gotten contaminated.
Since I first noticed this problem about 5 days ago I have noted:
No immediate change in RPM when depressing the clutch (no change in throttle input) during the episode
NOT bad gas, 5 different gas stations
Not water in the gas, problem got more pronounced after adding 'heat'
Ambient temperature doesn't seem to matter, however letting the car sit for 30+ min helps
No boost fluctuation.
Every gear
At first just right hand corners, both roads 35mph limit, with moderate throttle
Later hesitation, sometimes stall, after moderate/heavy decel
Does anyone know where the post about changing your fuel pump is?
Does anyone know if I could run a Walboro? 255 fuel pump w/o larger turbo, injectors, or
computer mod?
Anyone have any other ideas?
Thanks
06-20-2005, 04:13 PM
#15
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Join Date: Mar 2003
Location: Phoenix, AZ
Posts: 2,023
Car Info: Subaru Impreza WRX 2002
Originally Posted by jdepould
one thing you're not factoring is the relative humidity, in phoenix it can be 110 but you guys don't get nearly the humidty that we see in the great lakes region. the density of the air changes with the temp and humidity, thus affecting the performance of the motor. all things being equal, a motor will perform better with a cooler ambiet temp (say 60* compared to 95*), regardless of the operating temps.
It is possible that it wasn't bad gas, and some engine event (such as very strong knock or even an electrical problem) sent the ECU into "limp mode," which seems to be exactly what he is describing -- however, it isn't possible to have that happen without a CEL, which is the part of this whole discussion that doesn't add up.